package com.baomidou.kisso.common.bcprov.asn1;

import java.io.IOException;
import java.math.BigInteger;

import com.baomidou.kisso.common.bcprov.util.Arrays;

/**
 * Use ASN1Integer instead of this,
 */
public class DERInteger extends ASN1Primitive {

	byte[] bytes;


	/**
	 * return an integer from the passed in object
	 *
	 * @exception IllegalArgumentException if the object cannot be converted.
	 */
	public static ASN1Integer getInstance( Object obj ) {
		if ( obj == null || obj instanceof ASN1Integer ) {
			return (ASN1Integer) obj;
		}
		if ( obj instanceof DERInteger ) {
			return new ASN1Integer((((DERInteger) obj).getValue()));
		}

		if ( obj instanceof byte[] ) {
			try {
				return (ASN1Integer) fromByteArray((byte[]) obj);
			} catch ( Exception e ) {
				throw new IllegalArgumentException("encoding error in getInstance: " + e.toString());
			}
		}

		throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
	}


	/**
	 * return an Integer from a tagged object.
	 *
	 * @param obj the tagged object holding the object we want
	 * @param explicit true if the object is meant to be explicitly
	 *              tagged false otherwise.
	 * @exception IllegalArgumentException if the tagged object cannot
	 *               be converted.
	 */
	public static ASN1Integer getInstance( ASN1TaggedObject obj, boolean explicit ) {
		ASN1Primitive o = obj.getObject();

		if ( explicit || o instanceof DERInteger ) {
			return getInstance(o);
		} else {
			return new ASN1Integer(ASN1OctetString.getInstance(obj.getObject()).getOctets());
		}
	}


	/**
	 * @deprecated use ASN1Integer constructor
	 */
	public DERInteger( long value ) {
		bytes = BigInteger.valueOf(value).toByteArray();
	}


	/**
	 * @deprecated use ASN1Integer constructor
	 */
	public DERInteger( BigInteger value ) {
		bytes = value.toByteArray();
	}


	/**
	 * @deprecated use ASN1Integer constructor
	 */
	public DERInteger( byte[] bytes ) {
		this.bytes = bytes;
	}


	public BigInteger getValue() {
		return new BigInteger(bytes);
	}


	/**
	 * in some cases positive values get crammed into a space,
	 * that's not quite big enough...
	 */
	public BigInteger getPositiveValue() {
		return new BigInteger(1, bytes);
	}


	boolean isConstructed() {
		return false;
	}


	int encodedLength() {
		return 1 + StreamUtil.calculateBodyLength(bytes.length) + bytes.length;
	}


	void encode( ASN1OutputStream out ) throws IOException {
		out.writeEncoded(BERTags.INTEGER, bytes);
	}


	public int hashCode() {
		int value = 0;

		for ( int i = 0 ; i != bytes.length ; i++ ) {
			value ^= (bytes[i] & 0xff) << (i % 4);
		}

		return value;
	}


	boolean asn1Equals( ASN1Primitive o ) {
		if ( !(o instanceof DERInteger) ) {
			return false;
		}

		DERInteger other = (DERInteger) o;

		return Arrays.areEqual(bytes, other.bytes);
	}


	public String toString() {
		return getValue().toString();
	}
}
